1. Field of the Invention
This invention is in the field of composite articles of manufacture, such as tools subject to wear and attrition during use. Cutting tools, drawing and forming dies and rolls operable to engage and roll form work come within the categories of the composite articles of manufacture defined by the invention, all of which are subject to high heat and frictional wear during use.
2. The prior Art
The prior art has employed various tool structures and methods to increase their life span and improve their efficiency. Such tool structures have included the use of high strength steels, the provision of tool inserts made of metal carbides and other high strength compounds and alloys and the plating of hard metals such as chromium on the cutting edge portions of tool substrates. However, such material combinations are all subject to high attrition and wear when the tools made thereof are employed to cut or otherwise shape hard metals, ceramics and other hard materials. While natural diamonds have been bonded with adhesives and metal to tool supports, such as cutting tools and dies, they nevertheless suffer shortcomings which limit their life span and use. Tools made of natural diamonds are costly to make and maintain.
U.S. Pat. No. 3,703,766 relates to a cutting tool or blade having a honed sapphire filament bonded to an intermediate layer of glass which is bonded to a substrate. The filament defines the cutting edge of the tool. The structure is costly to produce and maintain. It is not satisfactory for many cutting operation.
U.K. Patent 1,521,841 defines cutting tool with an amorphous alloy defining the cutting edge of the tool.
U.S. Pat. No. 4,015,100 discloses alloyed surface structures of metal which may be used in tool fabrication.
U.S. Pat. No. 3,894,337 teaches the use of a single crystal of alumina having a cutting edge, mounted on a supporting substrate.